In recent years, the method of contactlessly supplying electrical energy to wireless power receivers in a wireless manner has been used instead of the traditional method of supplying electrical energy in a wired manner. The wireless power receiver receiving energy in a wireless manner may be directly driven by the received wireless power, or a battery may be charged by using the received wireless power, then allowing the wireless power receiver to be driven by the charged power.
For allowing smooth wireless power transfer between a wireless power transmitter which transmits power in a wireless manner and a wireless power receiver which receives power in a wireless manner, the standardization for a technology related to the wireless power transfer is undergoing.
As part of the standardization for the wireless power transfer technology, the Wireless Power Consortium (WPC) which manages technologies for a magnetic inductive wireless power transfer has published a standard document “System description Wireless Power Transfer, Volume 1, Low Power, Part 1: Interface Definition, Version 1.00 Release Candidate 1 (RC1)” for interoperability in the wireless power transfer on Apr. 12, 2010.
Power Matters Alliance as another technology standardization consortium has been established on March, 2012, developed a product line of interface standards, and published a standard document based on an inductive coupling technology for providing inductive and resonant power.
A wireless charging method using electromagnetic induction is frequently encountered in our lives, for example, is utilized by being commercialized in electric toothbrushes, wireless coffee ports and the like.
On the other hand, the WPC standard prescribes a method of performing communication between a wireless power transmitter and a wireless power receiver. However, the prescribed communication method is vulnerable to electrical, magnetic disturbances, and provides only one-way communication and thus cannot be applied to an application requiring information transfer from a power transmission unit to a power receiving unit. Furthermore, recently available communication methods provide only a slow transmission speed and there is a limit to an application requiring a large amount of information transfer.
Accordingly, it is required to provide a method of performing communication using a communication method other than the prescribed communication.